fsnotify: pass a file instead of an inode to open, read, and write

fanotify, the upcoming notification system actually needs a struct path so it can
do opens in the context of listeners, and it needs a file so it can get f_flags
from the original process.  Close was the only operation that already was passing
a struct file to the notification hook.  This patch passes a file for access,
modify, and open as well as they are easily available to these hooks.

Signed-off-by: Eric Paris <eparis@redhat.com>